The P300 ERP was measured in 10 subjects each for 9 days. The selection of instructions for subjects, the recording technique, the elimination of a few single trials significantly contaminated by eye movements, and the use of a correction procedure for ocular artifacts with calculable reliability and validity resulted in a set of data, in which 94% of the single trials were suitable for further analysis. The correction procedure relies on regression analysis. To reduce coherence between eyeblink activity and ongoing EEG, VEOG and EEG are averaged on eyeblinks. This yields a high reliability and validity of regression factors, determined per day, subject, and lead. In addition, this correction procedure allows for an estimation of the maximal error that must be taken into account. The efficiency of the procedure is demonstrated for single trials and averaged potentials.

In a double-blind placebo-controlled trial of 18 patients, methohexitone blocked objective signs of opiate withdrawal caused by a bolus injection of naloxone. Furthermore, in continuing the naloxone therapy for 48 hours, no withdrawal signs appeared. Levels of withdrawal distress returned to normal levels within six days. This approach can be regarded as an effective and well tolerated withdrawal therapy with low drop-out rates.

No abstract

In order to assess the course of methadone (Heptadone) substitution therapy, 29 inpatients at the Vienna Psychiatric University Clinic (21 males, mean age = 27 years, SD 4 years; 8 females, mean age 29.75 years, SD 5.28 years) who were addicted to opium tea or to a mixture of opium and heroin were investigated by means of computer-assisted "static"- and "light-evoked dynamic" pupillometry. Pupillary measurements were carried out before the start of withdrawal, on the 2nd day 48 h after the administration of 10 mg methadone, and again after the maximum and half of the maximum dose of methadone had been administered. The constricted pupils (the effect of opiate) showed dilatation after the withdrawal syndrome appeared, but immediately after the start of the detoxification treatment, as well as 1 day after administration of the maximum methadone dose a decrease of pupillary diameter was observed. The narrowing of the pupil was followed by an increase in pupillary diameter, which peaked 48 h after the last minimal dose of methadone and nearly reached the normal level. The widening of the pupil reflects an increase of noradrenergic activity under conditions of opiate withdrawal. An increase of spontaneous fluctuations was observed during withdrawal and was only inhibited by the maximum dose of methadone. Finally, pupillary dynamics (shortening of latency time and increase of relative changes) improved during therapy. The pupillary measurement corresponded with clinical observations as well as with self-evaluation during treatment. Thus pupillometry seems to be a useful instrument for assessment of treatment of opiate-addicted patients.

For opiate detoxification 6 volunteer opiate addicts were intravenously administered 10 mg naloxone within one hour while under barbiturate anesthesia. During administration of naloxone none of the patients demonstrated significant changes in the hemodynamic parameters of heart rate, mean arterial pressure, cardiac index, peripheral resistance or in the oxygen saturation. After patients awoke from anesthesia, they experienced no or only minimal withdrawal symptoms. Possible explanations for the suppression of withdrawal symptoms are discussed.